package com.luojiang.gateway.filter;

import org.springframework.cloud.gateway.filter.GatewayFilter;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.factory.AbstractNameValueGatewayFilterFactory;
import org.springframework.cloud.gateway.support.ServerWebExchangeUtils;
import org.springframework.http.HttpHeaders;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;
import org.springframework.web.server.ServerWebExchange;
import org.springframework.web.util.UriComponentsBuilder;
import reactor.core.publisher.Mono;

import java.net.URI;

import static org.springframework.cloud.gateway.support.GatewayToStringStyler.filterToStringCreator;

/**
 * @ClassName AccountRequestParameter
 * @Description 添加请求参数过滤器
 * @Author luojiang
 * @Date 2021/1/27 16:44
 */
@Component
public class AccountRequestParameterGatewayFilterFactory extends AbstractNameValueGatewayFilterFactory {

    @Override
    public GatewayFilter apply(NameValueConfig config) {
        return new GatewayFilter() {
            @Override
            public Mono<Void> filter(ServerWebExchange exchange,
                                     GatewayFilterChain chain) {
                URI uri = exchange.getRequest().getURI();
                StringBuilder query = new StringBuilder();
                String originalQuery = uri.getRawQuery();

                if (StringUtils.hasText(originalQuery)) {
                    query.append(originalQuery);
                    if (originalQuery.charAt(originalQuery.length() - 1) != '&') {
                        query.append('&');
                    }
                }

                // 进入参数封装环节
                System.out.println("======进入参数封装环节=======");
                HttpHeaders headers = exchange.getRequest().getHeaders();
                String token = headers.getFirst("token");
                String tenantId = headers.getFirst("tenantId");


                System.out.println("======结束参数封装环节=======");

                String value = ServerWebExchangeUtils.expand(exchange, config.getValue());
                // TODO urlencode?
                query.append(config.getName());
                query.append('=');
                query.append(value);

                try {
                    URI newUri = UriComponentsBuilder.fromUri(uri)
                            .replaceQuery(query.toString()).build(true).toUri();

                    ServerHttpRequest request = exchange.getRequest().mutate().uri(newUri)
                            .build();

                    return chain.filter(exchange.mutate().request(request).build());
                }
                catch (RuntimeException ex) {
                    throw new IllegalStateException(
                            "Invalid URI query: \"" + query.toString() + "\"");
                }
            }

            @Override
            public String toString() {
                return filterToStringCreator(AccountRequestParameterGatewayFilterFactory.this)
                        .append(config.getName(), config.getValue()).toString();
            }
        };
    }
}
